1. Field of the Invention
The present invention relates to coding of a video signal.
2. Discussion of the Related Art
Generally, compression coding means a series of signal processing techniques for transferring digitalized information via a communication circuit or storing digitalized information in a format suitable for a storage medium. Targets of compression coding include audio, video, character, etc. In particular, a technique of performing compression coding on a sequence is called video sequence compression. Video sequence is generally characterized in having spatial redundancy and temporal redundancy.
However, in predicting a macroblock having a size of 32×32 greater than 16×16 or a size greater than 32×32, prediction efficiency may be lowered using an inter prediction mode as a sub-macroblock type despite that there is a space capable of using more macroblock types.
As one prediction scheme of inter prediction coding and intra prediction coding is used for prediction of a macroblock only, compression performance may be degraded.
In case that most of a video includes a flat region, if the video is coded with a down-sampled frame, coding efficiency may be raised. Since partial information is removed in a downsampling process, it is able to provide a sufficient gain at a high bit rate due to a loss of quality.